A metamaterial is formed of a substrate made of a non-metal material and a plurality of man-made microstructures attached on a surface of the substrate or embedded inside the substrate. Each of the man-made microstructures is of a two-dimensional (2D) or three-dimensional (3D) structure consisting of at least one metal wire. Each of the man-made microstructures and a substrate portion to which it is attached form one metamaterial unit cell. Correspondingly, just like a crystal which is formed of numerous crystal lattices arranged in a certain manner, the whole metamaterial consists of hundreds of or thousands of or millions of or even hundreds of millions of such metamaterial unit cells, with each of the lattices corresponding to a metamaterial unit cell formed by one man-made microstructure and the substrate portion as described above.
Due to presence of the man-made microstructures, each of the metamaterial cells presents an equivalent dielectric constant and equivalent magnetic permeability that are different from those of the substrate per se. Therefore, the metamaterial comprised of all the unit cells exhibits special response characteristics to the electric field and the magnetic field. Meanwhile, by designing the man-made microstructures into different structures and sizes, the dielectric constant and the magnetic permeability of the metamaterial unit cells and, consequently, the response characteristics of the whole metamaterial can be changed.
In prior art, some uniaxial crystals such as calcites, quartzes and the like must be used in order to separate an electromagnetic wave beam. Because these crystals are mostly naturally occurring materials and their response characteristics to electromagnetic wave beams are invariable, it is impossible to flexibly control exiting angles of the separated electromagnetic waves. Consequently, these crystals cannot be widely used flexibly. Moreover, the natural crystals have limited sizes and also it is difficult to produce a man-made crystal with a large size; and if a number of crystals produced are spliced or bonded together to produce a larger crystal, then refraction and reflection caused by the joining or bonding surface would adversely affect the effect of separating the electromagnetic wave beam.